In the United States for every square meter of the reserves daily drops 132 of the micro-plastic particles, representing four percent of the total amount of dust. The annual flow of plastic particles in protected areas is estimated at 1000 tons annually, the equivalent weight of 120-130 million plastic bottles. According to the study, published in the journal Science, a large part of the wet deposition, the micro-plastic is brought in the reserves from nearby settlements, and the settling of dry particles is a consequence of global atmospheric transport.
Most of the studies of environmental pollution by microplastics affects the ecosystems of the world ocean: it is known that the particles penetrate in the organism of animals, which can cause clogging and damage to the intestinal tract. It is also known that microplastics are able to migrate along the marine food chains. However, the behavior of plastic particles in terrestrial ecosystems is also a concern of environmentalists: because its particles are much less dense than soil (0,65-1,8 vs ~of 2.65 grams per cubic centimeter), and can travel long distances with air transport. The most convenient ground for the study of global plastic pollution can be especially protected natural territories (SPNT), where limited human activity and therefore there are no direct sources of plastic.
Scientists led by Janice Battle (Janice Brahney) from the University of Utah investigated the deposition of plastic particles in the 11 major protected areas of the Western United States to establish their sources of income and to quantify the magnitude of plastic pollution in the background (i.e. not affected by anthropogenic activities) areas. For this weekly were selected and analyzed wet deposition (n=236) and monthly dry deposition (n=103), deposited in collectors stations installed in the framework of the national program of atmospheric deposition in all protected areas of the United States.